But that's the point - it's not like, say, switching to a different car make. It is, indeed, non-trivial to switch phone platforms. So why shouldn't we recognize this fact and hold the companies in the market to a different standard?
You can't force everything to be uniform and support all of the same features to make switching between manufacturers of a product-class "trivial". How's that part of a healthy free market? Requirements to that effect kills all creativity and specialization of products for different purposes. Android and iOS are different and that's a good thing!